Process for the manufacture of slub yarns

ABSTRACT

A process for the manufacture of slub yarns from continuous filaments, which comprises feeding continuous filaments through the inlet orifice of a guide tube at a feed rate superior to the withdrawal rate at the outlet orifice, and sucking them into a connecting tube by means of a sucking jet in such a manner that an increasingly enlarging open loop is formed; wherein a gaseous medium, in intervals and periods of time programmed by a control system, is blown into the connecting tube, thereby passing through the feeder tube of a blowing jet mounted to the end of the connecting tube which is adjacent to the guide tube; the gaseous medium causing a ligature of the neck of the open loop of the yarn, which loop so ligatured is subsequently united over its total length with the continuous filament.

United States Patent [191 Heichlinger et al.

[451 Dec. 17,1974

[22] Filed:

[ PROCESS FOR THE MANUFACTURE OF SLUB YARNS [75] Inventors: Norbert l-leichlinger, Munich; Karl Andiel, Bobingen, bothof Germany [73] Assignee: Hoechst Aktiengesellschaft,

Frankfurt/Main, Germany Jan. 9, 1973 [21 Appl. No.: 322,136

[30] Foreign Application Priority Data Jan. 11, 1972 Germany 2201147 [52] US. Cl ..'28/72.12, 57/157 F' [51] Int. Cl D02g 1/16 [58] Field of Search 28/72.12, 1.4; 57/34 B, 57/91, 140 BY, 157 F [56] References Cited UNITED STATES PATENTS I 3,433,007 3/1969 Myers 28/72.l2 X 3,457,715

7/1969 Eldridge et a1. 28/72.l2 X

3,517,498 6/1970 I Burellier et al.-. 28/72.l2 X

Primary Examiner -Louis K. Rimrodt Attorney, Agent, or FirmConnolly and Hutz [57] ABSTRACT A process for the manufacture of slub yarns from continuous filaments, which comprises feeding continuous filaments through the inlet orifice of a guide tube at a feed rate superior to the withdrawal rate at the outlet orifice, and sucking them into a connecting tube by means of a sucking jet in such a manner that an increasingly enlarging open loop'is formed; wherein a gaseous medium, in intervals and periods of time programmed by a control system, is blown into the connecting tube, thereby passing through the vfeeder tube of a blowing. jet mounted. to the end of the connecting tube which is adjacent to the guide tube; the gaseous medium causing a ligature of the neck of the open loop of the yarn, which loop so ligatured is subsequently united over its totallength with the continuous filament.

6 Claims, 3 Drawing Figures PROCESS FOR THE MANUFACTURE OF SLUB YARNS The present invention relates to a process for the manufacture of slub yarns madefrom continuous filaments, which comprises feeding continuous filaments through the inlet orifice of a guide tube at a feed rate superior to the withdrawal rate at the outlet orifice, and

duced on a large scale from synthetic filaments inunlimited quantities. These yarns are for example required for curtain or covering fabrics or other decorative materials, but also for ladies dress goods, where fabrics having an especially expressive structure are de-- sired.

In order to close this gap in the market, processes have been developed which ensure the. manufacture of synthetic yarns having irregularly placed slubs.

In some of these processes for example, these yarns are manufactured by introducing a yarn into a feed jet through which it is blown'against ascreen permeable to air (U.S. Pat. No. 3,296,785) which may have different porosities (U.S. Pat. No. 3,474,613), while from a second jet an air stream is blown in a counter-current against the screen, thus creating a turbulent zone in which slubs may form in the yarn. The slub yarn so obtained is united with a second yarn, and both yarns are pressed through a ply-interlacing jet and subsequently forwarded to a false twisting device.

In U.S. Pat. No. 3,116,589, a process is described wherein one or more yarn bundles are blown onto a screen simultaneously with an air stream; a second air stream coming from another jet is directed on the screen, and this stream, at a converging angle to the first one, produces the formation of slubs in the filaments. The slub yarn so obtained is then withdrawn by a conveying device in a counterscur rent direction to the second air stream, and subsequently wound up.

U.S. Pat. No. 3,174,271 describes the properties of the yarn obtained in accordance with US. Pat. No. 3,1 16,5 89. The yarn has slubs the size and distribution 2. laced in order to set the. slubs. Subsequently, the slub yarn is wound up.

All these. known processes for the manufacture of slub yarns and-the devices used in these processes provide slub yarns havingslubs the size and distribution of which is entirely random. Yarns are obtained containing thedesired slubs in completely irregular form and distribution, which means that the slubs may crowd in some sections of the yarn, while there are none or too small a number in other sections. Moreover, the slubs may be too short, so that they appear as knots, or they may be too long, so that they extend over more than one. filling yarn and thus give the fabric a faulty aspect.

In all these cases fabrics are obtained which do not meet the requirements, since they do not possess the desired structure as known from the titer differences of natural silk. I

Moreover, it has been observed that these yarns often contain so-called interlaced spots which clearly appear as flaws in the-fabric. The reason for these flaws are interlaced mono'capillaries in the yarn sections between 'the slubs, which sections are interlaced in the same manner as the slubs themselves.

It is thereforeone object of the present invention to provide a process and a device for carrying out this process which permit programming of the number and length of the slubs in the yarn. It is a further object to provide a process allowing a controlled manufacture of slub yarns, wherein the length of the slubs may be determined in accordance with the later application of the yarn, and which comprisesdistributing the slubs as desired so that they appear in an agreeable formin the finished fabric. A further object of this invention is to provide a slub yarn which,-'while being woven, neither does cause a faulty aspect of the fabric on account of slubs crowded nor show undesired interlaced spots.

Novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. I is a schematic diagram of apparatus performing a process which is one embodiment of this invention;

FIG. 2 is another schematic diagram of apparatus performing a process which is another embodiment of of which are entirely random. The yarn should contain at least 50 of such slubs per 914 m (1,000 yards) of yarn; the average length of the slubs being at least 24.5 cm, 10 to 30.percent of the slubs having lengths of more than twice the average. The slubs have an average titer of at least a triple of the starting titer, while 5 to 65 percent of the slubs have a titer which is at least 10 times greater than the starting titer.

From US. Pat. No. 3,433,007 it is known to manufacture a yarn from synthetic filaments which contains irregularly distributed slubsof random size, by continuously aspirating a yarn bundle of continuous filaments, by'means of an air stream, into a chamber providing an air turbulence, and by continuously withdrawing the yarn from this chamber at reduced speed. Before striking the withdrawing device, the slub yarn may be inter- These objects of the present invention are attained by blowing a gaseous medium, in intervals and periods of time programmed by a control system, into connecting tube (10) of the drawings, thereby passing through feeder tube (9) of blowing jet- (8) mounted to the end of connecting tube (10) which is adjacent to guide tube (5); the gaseous medium causing a ligature of the neck of the open loop of the yarn, which loop so ligatured is subsequently united over its total length with the continuous filament.

In a preferred embodiment of the process of the invention, the gaseous medium is blown by means of blowing jet (8') in the suction direction of sucking jet In a further preferred embodiment, the gaseous medium in blowing jet (8) is blown in a counter-current to the suction direction of sucking jet (7).

Preferably, the loops ligatured at their neck are united over their total length with the continuous filament by interlacing, using a gaseous medium. For interlacing the loops ligatured at their neck with the contin-. uous filament it is especially advantageous to introduce the gaseousmedium into interlacing jet (16) in a discontinuous manner, in the same intervals andperiods of time programmed, but with such a time lag as compared to the feed of blowing jet (8) that the loop liga tured only at its neck is completely united with the continuous filament in interlacing jet (16).

In all these variations of the process of the invention,

guide tube having a funnel shaped inlet orifice (4)- and a cylindrical top (13), furthermore a connecting tube a sucking jet (7) provided with feeder tube (6).

The distance between inlet orifice (9a) of feeder tube (9) of blowing jet(8) and the end (25) of connecting tube .(10) is advantageously greater by preferably a third than the longest slub to be produced.

It is especially advantageous to connect blowing jet (8) and interlacing jet (16) to a control system, preferably to magnetic valves (11) and (17) respectively, and to an aperiodic pulse generator (12) controlling the activity of blowing jet (8) and interlacing jet (16') by means of magnetic valves (11) and (17).

By aperiodic pulse generator there is to be understood any generator which, within optional limits, transmits pilot pulses in substantially random intervals of time. These intervals must not correspond exactly to random numbers of a purely mathematical signification, as they are defined in Handbook of Mathematical Functions of the National Bureau of Standards of the U.S.A., 1964, and' not to the pseudo-random numbers indicated in the same handbook.

A simple and advantageous aperiodic pulse generator is the installation which is described in its details in the examples, wherein several astable multivibrators are connected by means of an AND-gate in such a manner that apilot pulse is created only in the moment where all multivibrators transmit their starting pulse simultaneously. Although these pulse generators possess a periodicity of that time T which corresponds to the smallest common integer multiple of the periodicities of the single multivibrators, this periodicity period varies because of the astability of each of the circuit elements. By further connections, an upper and lower limit each of the pilot pulse sequence may be determined.

The'combination of devices necessary for carrying out the process of the invention will be betterunderstood by reference to the drawing of FIG. 1, which is a schematic representation of the above combination of devices. It shows filament'guide (2), feed rollers (3), guide tube (5) withcylindrical top (13), blowing jet (8) with feeder tube (9) in oblique position, magnetic valve (11) and aperiodic pulse generator (12) seriesconnected to it, furthermore, connecting tube (10) and sucking jet (7). The combination of devices comprises also interlacing jet (16) for setting the slubs, which process step has best results in the case where the filament inlet orifice of interlacing jet (16) is at a preferred distance of from 50 to 600 mm from the spot where the gas stream in blowing jet (8) strikes the open loop. The combination of devices comprises furthermore magnetic valve (17). inserted in the gas stream feeder tube, godet (18) with idler roll (19) and wind-up device /21 In the manufacturing process of the slub yarn having a programmed slub size and distributionaccording to the present invention, referring .to FIG. 1, a continuous multifilament (1) is forwarded first to a device for forming loops, thereby passing through filament guide (2) and feed rollers (3) which may consist of feed roll (3a) and contact roll (3b). The continuous filament passes through funnel shaped inlet orifice (4) into guide tube (5). Since the withdrawal rate of the continuous filament is lower than that of the feed, thefilament accumulates in guide tube (5). By continuously feeding in compressed air through feeder tube (6), a depression is produced in sucking jet (7), which sucks the overfed continuous filament in the form of an open loop through blowing jet (8) into subsequent connecting tube (10) connecting sucking jet (7) with blowing jet (8). Each time when a short'duration gas stream is loop of the continuous filament is closedby this gas stream pulse. The length of this loop is determined by the time interval between two gas stream pulses and the difference of filament feed and withdrawal rate. The loop leaves blowing jet (8), enters partially and temporarilyin cylindrical top (13) and passes then through outlet orifice (14) over guide pins (15a) and (15b) to interlacing jet (16), while the gaseous medium escapes through cylindrical top (13) and connecting tube (10). Interlacing jet (16) is fed with gaseous medium by means of the same control mechanism and magnetic valve (17) ina'time lag over blowing jet (8) to be' determined in each case, so that the gas stream pulses striking the yarn interlace theloops formed with the continuous filament and thus set them, while the yarn sections between the slubs are substantially maintained in their original state. The slubyarn so obtained iswithdrawn by means of godet (l8) and 'idler roll (19) and wound up on bobbin (21).

Suitable starting materials for the process of the invention are all yarns made from synthetic high polymers, for example, from polyamides, polyacrylonitrile, but above all yarns made from high molecular weight polyesters, for example polyethylene terephthalate, having filament titers of from 1.0 to l0.0 dtex, especially from 1.3 to 3.0'dtex, and totaltiters of from 50 to 3,000 dtex, especially from 100 to 400 dtex. The starting material may-be drawn filaments withdrawn from the drawing cop and-fed to the described installation of devices, or the spun yarn is used which is drawn immediately before processing and forwarded directly to the blowing jet without winding it up after drawing.

Within the cited range of titers, the filaments used may continuous filaments having alatent crimp. This latent overfeed (percent) crimp may be developed by known methods eitherin the course of the manufacturingprocess of the slub.

yarn, or after it in the finished yarn, or later in the fabric itself. I

The manufacturing process of the present invention is generally carried out at .a feed rate of the yarn of through which a continuous airstream is fed in to cause, the desired depression.

In a modified embodiment devices which in principle corresponds totheinstallafrom l00'to 1,000 m/min, preferably from 300 to 80 0;"

' m/min. The feed ratemay also exceed these limits, but

the feed rate of feed rollers (3) must always be higher than the withdrawal rate of godet (18),- so that loop for-' mation is possible. This. difference between feed rate in m/min and withdrawal ratein m/min is the overfeed, which is indicated in percent and defined as follows:

r eed ratew1thdrawalrate X 100 withdrawal rate The overfeed depends on the desired average of the slubs and their distribution. A preferred overfeed range is-from 3 to 20 percent.

The gaseous medium forwarded to the. blowing jet and the, interlacing jet in predetermined time'intervals is preferably compressedair, but may be also steam or another gas. Wheneverpo'ssible, this gas is generally used at normal temperature. In special cases, however, it may be advantageous to use a'heated gas, for example when a latent crimp of the filamentsis to be simultaneously developed: The gas pressure before the jets is generally from 0.5. to 7.0 atm/g, for the blowing jet- I is is preferably from 1.0 to 3.0 atm/g, and for the inter tion of FlG. l, but'is completed by filament guide (23') I and feed rollers (24). The additional filaments have a -titer' of from 30 to '1 ,000 'dtex, preferably from 50-to 200 .dtex. It is without importance for the process of the invention whether this additional filament is a continuous filament made fromjsynthetic high polymers or a fiberyarn made from natural or synthetic fibers.'Additional filament (22 passing through filament guide (23) and feed rollers (24) consisting of'feed' roll (24a) and contact ro'll (24b )-is fowarded to interlacing jet (16), through which it passes together with the' slub yarn. Interlacing jet (l6) and blowing jet (8) receive lacing jet preferably from 3.0 to 6.0 atm/g. The sucking jet is fed with compressed to 3.0 atm/g. f

The, gas is fed to the blowing and interlacing jets, res'pectively, by the control system; This control'system air at a pressure of from 0.8

may for example consist of two magnetic valves which are inserted in the gas feeder tubes of the blowing and interlacing jets, respectively, and which receive pilot pulses with corresponding time lag .by an aperiodic pulse generator. This aperiodic pulse generator may be programmed, within an optional range, with the averagen'umber of gaspulses per'unit of time, theaverage and maximum break time. By this program, the length and distribution of the slubs within the adjusted range is determined. a v

The invention, however, is not limited to the cited method of control.- It is also'possible touse pneumatic control pistons or other suitable devices.

in the drawings which illustrate the invention, FlGj3 shows the main parts of the combination of devices in embodiment of the process of the invention. 1 r FIG. 3 shows blowing jet (8 with guide tube (5), funnel shaped inlet orifice (4), cylindrical top l3) and the .sjzed a n The novelprocess of the invention permits a series of short time pulses of a gaseous medium in the same time vvintervals, which pulsesset the slubs and unite the additional filament with the slub yarn. Withdrawal of the set slub yarn is carried outby means of godet (18) with 1 ider roll (19), and theyarn is wound up by means of wind-up device (20/21). The feed rate of the additional filament normally is not inferior to the withdrawal rate, preferably the same;

but it 'may be adjusted tobe up to- 1 percent superior to the withdrawal rate. r

' The process of the invention provides slub yarns the slubs of which generally have a titer'three to four'times that of the starting yarn. The strength of the slub yarns obtained is generally sufficient for the subsequent pro. cessing and the manufacture of the fabrics. For applications requiring-"an especially high. filament strength, it

is advantageous to manufacture a slub yarn with addi- 'tional filament which provides greater. strength; Immediately after their .manufacture, the slubyarns may be modifications, for example with'respect to filamentfeed, withdrawal, number. of blowing pulses per unitof 1 time and break times between the pulses. The process time of the breaks betweentwo pulses, and aminimum thus presents the advantageof allowing the' manufacture of various-yarns, eaehgiving the'finished fabric a different structure. lt is possible to manufacture yarns the slubs ofwhichmay differ in-their'varied'average a length or in their distribution, or yarns containing slubs accordance with this invention, and FIG. 2 a modified control mechanism connected via feeder tube (9), the

control mechanism consisting-for example of magnetic valve (11) and aperiodic pulse generator 12). The' lower part of blowing jet (8) is connected to sucking jet l (7) by means of connecting tube (10) which may be of rigid or flexible material. It is especially advantageous toprovide the distance between inlet'orifice (9a) of feeder tube (9 of blowing jet (8) and end (25) of connecting tube (10) insuc'h av manner that is atleast 13 because of 'too short or t oolon g slubs.

.The following examples illustrate the 'invention.

EXAMPLE Using the installation of FIG. 1, a zero-twist m'ultifilament yarn made from polyethylene terephthalate,

having a titer of 200 dtex and 140 monocapill'aries is forwarded; at a rate of 430 m/min, to the blowing j'et times greater than the longest-slub to be produced.

Sucking jet 7) provided with feeder tube (6) 'where loops are formed. Theblowingjetis fed with compressed air at 2.15'atm/g, the sucking jet withcompressed airat 1.9 atm/g, and the interlacing jet with compressed air at 5.2 atm/g.

' The blowing jet and the interlacing jet are not fed with a constant air stream, but single air pulses, about a of the process of themvention', an additional-yarn is combined with the slub v yarn. FIG. 2 shows the corresponding combination of 1 13 per minute, are transmitted to them. The blowing slubs as the yarn'described'iii Example- 1, but the slub time of such an'air pulse is adjusted to 0.07 seconds in.

the aperiodic pulse generator, and the breaks between the air pulses are programmed to be from 0.1 to 0.9

seconds, so that the duration of the breaks varies within the predetermined time range. I 1

The aperiodic pulse generator consists of fourastable multivibrators having a periodicity of ll, 139, 219

and 262 msec respectively; at the same duration of' each pulse and break. Each pilot pulse of this generator sets off three monostablemultivibrators; the first adjusts the time of air pulse to 0.07 seconds the second limits the time interval between, tow air pulses to a mineffect isslightly reduced by the, additional'yar'n. The

slubs have a titer being from 2.5 to3. 15 times greater than that of the yarn sections between theslubs. Theadditional yarn causes also a better setting of the slubs, 99 percent of which having a strength of at least 350 g.

What is claimed is: i I

1. A process for the manufacture of slubyarns-from continuous filaments, which comprises feeding continuous filaments through the inlet orifice of a guide tube at a feed rate superior. to the withdrawal rate at the outimum of 0.1 seconds, and the third, after a break ofO.'9

seconds, sets off an air pulse if in the meantime there has been no pilot pulse from the generator; i-.e., it determines the upper limit of the breaks. The periodicity of this aperiodic pulse generator is' calculated to be 805 529 '724msec, i .e., more than 9 days. In th'e measuring times examined, more than'SO percentof .all pulses were from 150 to 350 msec, only 4 percent were from 700 to 900 msec. l s

The finished slub yarn leaving the interlacing jet vis let orifice, and sucking them into a connecting tube by means of a sucking jet'in'such a manner thatan increasingly enlarging open loop is formed; wherein a gaseous medium, in intervals and periods: of time programmed conveyed to the-win'd-updevice by means of the with drawing godet at a rate of 408 m/min. i

500 slubs. of the yarn so manufactured have a lengt of from 17 to 159mm. Most frequent are slubs having a length of about 53 mm, and they are from 3.07 to i 3.91 times thicker thanthe titer of the startingyarn.

The yarn sections between'the slubs have a length of from L1 to 6.5 m. For about 99 percent of the slubs so prepared, a tensile strength of from 200 to 800 g is obtained. EXAMPLE 2 in the installation as shown in FIG. 2, a continuous m ultifilamen't yarn made frompolye'thylene terephthalate, having a titer of 200 dt'ex and 140 nionocapillaries,

is converted to a'slub yarn, thereby'maintaining thedata as adjusted in Example 1. In the interlacing jet," this slub yarn is interlaced with an additional yarn having a titer of 70 dtex and monocapillaries, which yarn isfed into the interlacing. jet by means oa second 1 by a controlsystem, is blown into the connectingtube;

thereby passing through the feeder tube of a blowing jet mounted to the endof the connecting tube' which is ad-.

. jacent to the guide tube; thegaseous medium causing I a ligature of the neck of the open loop of the yarn, which, loop so ligatured is subsequently unitedover its total length with the continuou sfilament. 2. A process as claimed in claimfl, wherein the gase- .ous medium is-guided throughthe blowing jet in the suction direction of the sucking jet.

3. A process as claimed in claim I wherein thegaseous, medium is. guided through the blowing jet in a counter-current of the suction direction of the sucking jet.

-ligatured only at their neck are united over their total time programmed; but with such a time lag as compared to the feed of the blowing jet that the loopliga feed mechanism at'a rate of 408 m/min. The slub yarn obtained is withdrawn by the withdrawal godet at a rate of 408 m/min and wound on the wind-up device.

The yarn so obtained has the same distribution of tured'only at its neck is completely united with the continuous-filament in the interlacing jet. v v 6. A processas claimed in. claim 1, wherein an additional continuous filament is introduced into the interprocess as claimed in claim 1, whereinithe loops 

1. A process for the manufacture of slub yarns from continuous filaments, which comprises feeding continuous filaments through the inlet orifice of a guide tube at a feed rate superior to the withdrawal rate at the outlet orifice, and sucking them into a connecting tube by means of a sucking jet in such a manner that an increasingly enlarging open loop is formed; wherein a gaseous medium, in intervals and periods of time programmed by a control system, is blown into the connecting tube, thereby passing through the feeder tube of a blowing jet mounted to the end of the connecting tube which is adjacent to the guide tube; the gaseous medium causing a ligature of the neck of the open loop of the yarn, which loop so ligatured is subsequently united over its total length with the continuous filament.
 2. A process as claimed in claim 1, wherein the gaseous medium is guided through the blowing jet in the suction direction of the sucking jet.
 3. A process as claimed in claim 1, wherein the gaseous medium is guided through the blowing jet in a counter-current of the suction direction of the sucking jet.
 4. A process as claimed in claim 1, wherein the loops ligatured only at their neck are united over their total length with the continuous filament by interlacing, using a gaseous medium.
 5. A process as claimed in claim 1, wherein the gaseous medium for interlacing the loops ligatured at their neck is introduced into the interlacing jet in a dicontinuous manner, in the same intervals and periods of time programmed, but with such a time lag as compared to the feed of the blowing jet that the loop ligatured only at its neck is completely united with the continuous filament in the interlacing jet.
 6. A process as claimed in claim 1, wherein an additional continuous filament is introduced into the interlacing jet. 